[wp-trac] [WordPress Trac] #32597: mediaelement.js high CPU usage in Firefox

WordPress Trac noreply at wordpress.org
Tue Sep 15 19:33:03 UTC 2020

#32597: mediaelement.js high CPU usage in Firefox
 Reporter:  afercia                  |       Owner:  (none)
     Type:  defect (bug)             |      Status:  new
 Priority:  normal                   |   Milestone:  Awaiting Review
Component:  External Libraries       |     Version:
 Severity:  normal                   |  Resolution:
 Keywords:  reporter-feedback close  |     Focuses:
Changes (by desrosj):

 * keywords:  reporter-feedback => reporter-feedback close
 * milestone:   => Awaiting Review


 I'm not sure how this could be improved on WordPress' side of things
 without a change upstream in mediaelements (perhaps a new option to
 disable this buffering animation). It
 [https://github.com/mediaelement/mediaelement/blob/master/docs/api.md does
 not seem like the animation can be disabled in the current version of the

 @afercia is there any way to confirm that the ~20% CPU increase is being
 caused by the animation itself and not the fact that the window begins
 downloading and processing the audio file? Also, can you confirm that this
 does not just happen in the Classic Editor, but in the block editor and on
 the front-end as well?

 Also, I attempted to find the Firefox issue that you referenced but did
 not have much success. If you are able to recall the issue, can you please
 share the link here?

 I am going to mark this with a `close` recommendation with a suggestion to
 `report-upstream` unless it becomes apparent how to fix this on the
 WordPress side.

 Noting #51315 as related, as this will update the library from
 4.2.12 to the latest release, 4.2.16], though nothing in the changelog
 references the performance issue documented here.

Ticket URL: <https://core.trac.wordpress.org/ticket/32597#comment:5>
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